Bogs for a second and then takes off

[StickWalker]

First off, I replaced the injectors with new FIC injectors and pinned the secondaries open with Hiabecks chip for 2ndy deletion. I did this swap around 500 miles or so ago and also changed the fuel filter at the same time.

Now the issue starts after a few minutes of driving before that it runs great. (Never has an issue from a stop) When the issue occurs I am in a gear coasting (foot off the gas) at around 2-4000 rpm, and when I hit the gas pedal it bogs down for a second or so and then takes off and pulls to 7000 no problem. It only ocurrs after a moment of high vacuum once its warm. I have replaced the MAP sensor and hose with no change, drove around with a fuel pressure gauge on the windshield which shows around 41 psi with the foot off the gas, and goes up to 51 when I press on the gas.


I've checked for vacuum leaks and cant find any. The only thing I have noticed is that #4 cylinder plug seems like it's running rich, Ohm's 16 when cold, havent checked when hot.

If anyone has any other ideas without just throwing parts at I would appreciate it.

Thanks,
Don

[Roadster]

IMO, it may depend on what gear you are in at the time you hit the gas pedal, and the speed that you are traveling. When I first got my Z 6 months ago, I noticed a similar situation, but found out that if you drop a gear or two and bring up the r's, no problem. I thought that at any gear with the LT5 it would be instant, and again depends on your speed and what gear you are in.

I don't think that one plug even if running rich would cause that situation, IMO, it would have to be loaded and fouled out for you to feel anything.

Just had ours out today, always a great ride.....have fun.....

[XfireZ51]

Did this happen before the 2ndaries were deleted?

[StickWalker]

Dom, this didnt happen before the secondaries were deleted, and there is not bogging for 5 minutes or so after starting it. Then ,only after coasting with the foot off the gas and like your slowing down for a light and then you get back on it, it falls on its face for a second and then takes off like it never happened.

Don

[We Gone]

I'm sure the secondary injectors are not on in the first 5 min. after start up as the temps have to be up before they will go active. This may be why you don't have an issue in the first 5 min. or with no secondary's are the injectors all working from start-up?

[StickWalker]

Steve, I believe the secondaries are all on all the time with the deletion chip. Plus this didnt happen for the first 3-500 miles after I deleted them. After searching some older threads I'm wondering whether an O2 sensor has died since the car has 100K miles on it.

Don

[Dynomite]

I have a 91' with secondaries eliminated and RC Injectors.

Three 90's all with RC injectors and secondaries including starter reconditioned like new.

All four ZR-1s have Haibeck chips.
All four have TB coolant blocked at Injector Housings.
All four have the Starter Relay installed.
All four have Jerry's gaskets and SS bolts.
All four have full compliment of Carter Bling

All four accelerate like greased lightning with NO bogging or hesitation in any gear at all RPMs

Oh.........And a 90' (L98) with Haibeck Chip......also greased lightning

[WVZR-1]

Originally Posted by Dynomite

All four accelerate like grease lightening with NO bogging or hesitation in any gear at all RPMs

Oh.........And a 90' (L98) with Haibeck Chip......also grease lightening

Just what is "grease lightening"?

I've seen "GREASED LIGHTNING" used in reference to maybe fast or speedy BUT "LIGHTENING" confuses me.

[Dynomite]

Originally Posted by WVZR-1

Just what is "grease lightening"?

I've seen "GREASED LIGHTNING" used in reference to maybe fast or speedy BUT "LIGHTENING" confuses me.

I am a poor speller

Just got done making a set of New Oil Cooler SS Braided Hoses with Aeroquip re-usable fittings for a 90' ZR-1 and they fit perfectly first try.
I cannot spell "Aeroquip re-usable" sometimes but the hoses are perfect

I will take a photo tomorrow after I degrease (here I go again ) the little bit of oil spilled while doing the change over to SS Braided hoses.

I will try some runs tomorrow also to see if I can get it to bog or hesitate at all.

[WVZR-1]

Originally Posted by Dynomite

I am a poor speller

LOL - me too I believe